A Look at Particulate Flows in Tribiology, Nanomanufacturing, and on Mars
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Date: 02-10-2006
Start Time:
10:00am
End Time: 11:00am
Speaker: C. Fred Higgs, III
From:
Carnegie Mellon University
Location: 233 Mudd
Hosted by:
Center for Integrated Science
Abstract:
Particulate flows are applicable to a wide-range of engineering
problems spanning the tribology, nanomanufacturing, and granular flow
arenas. They are used to planarize nanoscale devices on silicon wafers
during the semiconductor integrated circuit (IC) manufacturing process
and the fabrication of next-generation data storage. They have also
been explored as dry alternative lubricants for high-speed applications
in both powder and granular forms. The first segment of this
presentation will focus on work conducted in chemical mechanical
polishing (CMP). CMP is one of the processes involved in the
manufacturing of semiconductor ICs, where slurry with nano-size
particles is sheared between a silicon wafer and a polymeric pad. In
this reverse-tribology problem, the slurry (“wet” particulate flow)
wears the thin film layers on the wafer surface. Consequently, the
ultra-thin layers are polished and planarized. The slurry is a complex
mixture of Newtonian fluid and nanoparticle abrasives, which makes the
CMP problem continuously unpredictable. This talk will explain how we
are attempting to solve this multi-physics, multi-scale problem with
modeling and experiments. The second segment of the presentation will
showcase work that has been done with dense “dry” particulates in
sliding contacts, namely powder lubricants and granular materials.
These particulate flows have been proposed as alternative lubricants to
oils, which are unable to sustain loads at very high temperatures. The
Particle Flow & Tribology Laboratory is also currently developing
the first “granular journal bearing” to study the hydrodynamic behavior
of granular flows in rough and loaded rolling contacts. This instrument
will be valuable for studying granular materials behavior for the
development of next-generation planetary rover technology for Martian
exploration.
Biography:
C. Fred Higgs, III received his B.S. in mechanical engineering from Tennessee State University. He received his M.S. and Ph.D. in mechanical engineering at Rensselaer Polytechnic Institute (RPI). Prior to coming to Carnegie Mellon University, he completed his post-doctorate at the Georgia Institute of Technology in the Woodruff School of Mechanical Engineering. He has authored or co-authored over 25 archival papers and has been an invited speaker at numerous international conferences, including the Materials Research Society (MRS) CMP Symposium, the International VLSI/ULSI Multilevel Interconnection Conference (VMIC), the International Multi-level Interconnect Conference (IMIC), and most recently, the 2006 MRS Symposium: "Nanostructured and Patterned Materials for Information Storage”. An assistant professor in the mechanical engineering department at Carnegie Mellon, he has recently been appointed an Associate Editor of the STLE Tribology Transactions Journal. Dr. Higgs is a professor in the “Alfred P. Sloan PhD Program”, which supports professors and their students at select institutions who are recognized as magnets and mentors to minority PhD students in engineering and science.